red bugs is easily treatable with Interceptor, a dog dewormer. I believe it works at attacking the bug through the blood and effecting it's brain because it doesn't have a blood/brain barrier.
I believe fish and some invertebrates, as well as dogs and humans, have this blood brain barrier so it is harmless to us.
Some dogs, like Dalmations, have some genetic problem where the blood brain barrier is not always complete, so sometimes it's not used on them.
Checkout melevsreef.com for his dosage.
edit: Shrimp / hermits / carbs, but not snails, will die from the treatment too.